Cod sursa(job #3207974)

Utilizator racoltaRacolta Victor racolta Data 27 februarie 2024 11:19:24
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.58 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

struct muchie
{
    int y,c;
};
const long long INF=1000005;
const int NMAX=50005;
vector<muchie> G[NMAX];
int dist[NMAX],viz[NMAX];
int n,m;

void read()
{
    f >> n >> m;
    for(int i=1;i<=m;i++)
    {
        int x,y,c;
        f >> x >> y >> c;
        G[x].push_back({y,c});
    }
}

void init()
{
    for(int i=1;i<=n;i++)
    {
        dist[i]=INF;
    }
    dist[1]=0;
}

queue<int> q;

void bellmanford(int nod)
{
    q.push(nod);
    while(!q.empty())
    {
        int nodc=q.front();
        q.pop();
        viz[nodc]++;
        if(viz[nod]==n)
        {
            g << "Ciclu negativ!";
        }
        for(auto vec:G[nodc])
        {
            if(dist[vec.y]>dist[nodc]+vec.c)
            {
                dist[vec.y]=dist[nodc]+vec.c;
                q.push(vec.y);
            }
        }
    }
}

int main()
{
    read();
    init();
    q.push(1);
    while(!q.empty())
    {
        int nodc=q.front();
        q.pop();
        viz[nodc]++;
        if(viz[nodc]==n)
        {
            g << "Ciclu negativ!";
            return 0;
        }
        for(auto vec:G[nodc])
        {
            if(dist[vec.y]>dist[nodc]+vec.c)
            {
                dist[vec.y]=dist[nodc]+vec.c;
                q.push(vec.y);
            }
        }
    }
    for(int i=2;i<=n;i++)
    {
        g << dist[i] << " ";
    }
    return 0;
}